Indole-2,3-dione-3-oxime derivatives are useful pharmaceutical products. WO 98/14447 (NeuroSearch) describes indole-2,3-dione-3-oxime derivatives useful for antagonising the effect of excitatory amino acids. These compounds are prepared by conventional methods of chemical synthesis including the step of reacting an 1H-indol-2,3-dion with an amino derivative. More specifically WO 98/14447 describes indole-2,3-dione-3-oxime derivatives, some of which exist as racemic mixtures.
It is often desirable, and sometimes subject to regulatory demands, to undertake drug development on specific enantiomers rather than racemic drugs. This rationale is based on the findings that often the desired characteristics of chiral compounds reside with one of its enantiomers, while the other enantiomer might in fact add to a potential toxicological effect of the drug.
In order to allow thorough investigation of each enantiomer, processes for obtaining enantiopure preparations of chiral compounds are of significant importance for drug development.
EP 439779 (Chisso Corp.) describes a process for producing optically active hydroxy lactones using enzymatic transesterification. However, a method of preparing enantiomers of indole-2,3-dione-3-oxime derivatives is not described.
EP 467132 (Chisso Corp.) describes 4-substituted-2-hydroxybutanoates and a process for producing them. However, a method of preparing enantiomers of indole-2,3-dione-3-oxime derivatives is not described.